Anna Bay Acid Sulfate Soil Assessments

In recent years there has been increasing awareness of the impacts of acid sulfate soils in the Anna Bay sub-catchment, which discharges into the Port Stephens – Great Lakes Marine Park. Greater movement of acidic groundwater has resulted in fish kills, poor water quality affecting oyster cultivation, reduced stock production and a deterioration in downstream environmental values.

This report provides the results of detailed on-ground assessments of the distribution and impacts of acid sulfate soils. These assessments included:

a review of all previous studies

water quality monitoring and chemical analyses

collection and analysis of soil cores

cross-sectional drain profiling

digital elevation data (LiDAR)

land surveys

The assessments identified the presence of acid sulfate soils across the catchment with two key ‘hotspot’ areas of soil acidity.

The report also identifies on-ground works that would be most effective at retaining high groundwater levels to manage acid export, while ensuring better drainage of surface waters following floods and severe rain events.